The subject of the present invention is a spoke nipple comprising a body of substantially undeformable material with a head and a shank which have an at least partially threaded axial hole for housing the thread of a spoke. The invention also relates to a method of manufacturing the nipple.
Nipples having the characteristics indicated above are used widely in the construction of spoked wheels, for restraining the threaded end of the spoke on the rim of the wheel.
In this field, it has been noticed in the past in wheels with conventional spokes and, more recently, with some types of spokes, particularly so-called straight spokes which do not have a bend at the axially opposite end to the thread for the attachment of the nipple, that the nipple may slowly unscrew under load, in use. This leads to inadequate functioning of the wheel owing to the gradual loosening of the nipples, and consequently to a dangerous weakening of the wheel as a whole.
To prevent this problem, some wheel assemblers use special adhesives or glues which are spread on the threaded portions of the spoke and/or of the nipple before it is tightened. However, the effect of these glues is difficult to control--in some cases they may completely block the nipple, preventing its subsequent removal--and, in any case, the effect is cancelled out if the wheel is subjected to successive adjustments of the tension in the spokes involving the release of one or more nipples.
The technical problem upon which the invention is based is that of providing a spoke nipple which overcomes the problems complained of with reference to the prior art mentioned.